This invention relates to a breathing apparatus enabling a person to function in water or irrespirable gases, the breathing apparatus suitable, in particular, for considerably short-time diving in relatively shallow water.
Conventionally, various kinds of breathing apparatuses are used for enabling people to breath in environments in which it is difficult to maintain natural respiration. A typical example of the conventional breathing apparatus is a scuba, i.e., a self-contained under water breathing apparatus which has a regulator connected to an air cylinder generally containing 12 to 14 liters of high-pressure air compressed to about 150 or 200 atmospheres. However, since the scuba enables a person to dive in a water depth, e.g., of more than 30 meters and also to dive for an amount of time, e.g., of more than 30 minutes, it is dangerous for the person to use the scuba without knowing the diving medical science and the diving physics. Moreover, since the scuba weighs no less than 20 kg, and also since it is not easy to handle, the scuba users are required to receive special training in advance of using it. For this reason, it has not been possible for many people to enjoy scuba diving, and thus all that has been readily available to them is snorkelling